1. Field of the Invention
This invention relates to a process for producing a slow release composite having a physiologically active substance encapsulated therein, which comprises preparing a system wherein one or more physiologically active substances are in contact with protein from one or more protein sources, and bringing said system into direct contact with steam at temperatures between 50.degree. C. and 100.degree. C. to denature the protein and make the same hydrophobic, to thereby make a slow release composite having the physiologically active substance dispersed, fixed and encapsulated therein. And this invention also relates to a process for producing a slow release composite which comprises preparing a mixture of one or more hydrophilic polymerizable monomers containing body fluid and/or isotonic solution, protein from one or more protein sources, and one or more physiologically active substances, and bringing said mixture into direct contact with steam at temperatures between 50.degree. C. and 100.degree. C. and irradiating with light or ionizing radiation, said contact with steam being performed either before or simultaneously with irradiation with light or ionizing radiation.